The declaration that:
it is emphatically the province and duty of the Judicial department to say what the law is[1] comprehends the following principle; that the Supreme Court is the final interpreter of the law and its declaration[2], that the doctrine of separation of powers assign the interpretation and declaration of law and all state actions to the constitutional courts and no authority other than the Superior Courts can arrogate to themselves the power to exclusively and authoritatively interpret, and set the stage for execution of law and the constitution.[3]

By virtue of Article 13 of the Constitution, the declaratory power of the Court arises from its authority to adjudge laws which are inconsistent with the Constitution and to declare them void. The Court is the final and permanent assembly of producer of law.[4]

Article 141 of the Constitution provides that the law declared by the Supreme Court shall be binding on all courts within the territory of India. The general principles laid down by the Supreme Court are applicable to each individual including those who are not party to an order.[5]

A special leave petition (SLP) does not by itself render the impugned decision a binding precedent. When reasons are given by the Court for dismissing a SLP, the decision attracts Article 141.[6] A mere reading of Article 141 hints at its expansive and all-inclusive nature. In cases where a number of petitions are disposed of by the High Court vide a common judgment and only one appeal is filed and the apex court decides it, the parties to the common judgment should intervene during the proceedings are going on in the Supreme Court and cannot later plead ignorance of such a fact.[7]

The Supreme Court is not only a constitutional court but is at the top of the hierarchy of our judicial system. By virtue of Article 141, its decision is the law of the land. Its main role is to interpret constitutional provisions and to promote governance by rule of law.[8] Its role, therefore, is to really interpret the law and decide cases coming before it, according to law.[9]

Stare decisis
Article 141 incorporates the English law doctrine of stare decisis.[10] The doctrine envisages that lower courts are bound by decisions of higher courts.[11] This doctrine is based on the principle that laws that govern the society at large should be fixed, definite and known. The doctrine should always be strictly adhered to by the courts in order to avoid confusion and uncertainty.[12]

Ratio decidendi and obiter dicta
A decision is binding not because of its conclusion but by virtue of its ratio and the principles laid down therein.[13] The ratio decidendi is the underlying principle, the general reasons or the general grounds upon which the decision is based as distinct from the special peculiarities of a case, which gives rise to its decision.[14]

Obiter dicta are statements which are not part of the ratio viz., observations by the Court which are not binding statement of law.[15] The obiter dictum is a mere observation or remark made by a court while deciding the actual issue before it and these casual remarks are considered or treated as beyond the ambit of the authoritative or operative part of the judgment.[16] Well considered obiter dicta of the Apex court are taken as precedents and binding under Article 141.[17]

Per incuriam
Incuria literally means carelessness. A decision rendered in ignorance of a previous binding decision of its own or of a court of coordinate or higher jurisdiction or ignorance of the terms of a statute or of a rule having the force of law locks precedent value, is one such exception and is described as per incurium judgement.[18]

Prospective Overruling
This is now a well accepted notion in decision making. Prospective declaration of laws is a device innovated by the Supreme Court to avoid reopening of settled issues and prevents multiplicity of proceedings. This is basically to avoid unnecessary litigation and is done in larger public interest.[19]

Supreme Court not bound by its own decisions
The Constitution has not decidedly enacted that Supreme Court will be bound by its own decisions.[20] This is necessary for proper development of law and principles of justice. No constitutional embargo prevents Supreme Court from departing from its previous decision.

Advisory opinion given under Article 143 is binding
Article 143 deals with the power of President to consult the Supreme Court. Opinion expressed by the Apex court under this provision will be binding on all courts in view of Article 141.[21]

Decision by a foreign court
The decisions of the English courts being merely of persuasive nature will not ipso facto justify an application to reconsider an earlier decision of the Supreme Court.[22]

Conclusion
The Supreme Court of India is on the top of the hierarchy of courts and hence it is imperative for its decisions to have a finality attached to them. This finality can only come from the binding nature of these decisions so that an end can be marked to the litigation process. Hence, the binding nature of the Supreme Court decisions is an important aspect of the justice delivery system in the country.

End-Notes:

1. Marbury v. Madison, 5 U.S. (1 Cranch) 137 (1803).
2. Rajeswar Prasad Misra v. State of West Bengal, 1966 (1) S.C.R. 178.
3. Cooper v. Aaron, 358 U.S. 1 (1958).
4. P. Kannadasan v. State of Tamil Nadu, A.I.R. 1996 S.C. 2560.
5. Ganga Sagar Corporation v. State of Uttar Pradesh, A.I.R. 1980 S.C. 286.
6. Union of India v. All India Services Pensioners Association, A.I.R. 1988 S.C. 502.
7. Shenoy and Co. (MIs) v. Commercial Tax Officer, Circle II, Bangalore, A.I.R. 1985 S.C. 621.
8. S.R. Bommai v. Union of India, A.I.R. 1994 S.C. 1918.
9. Secretary, State of Karnataka v. Umadevi, (2006) 4 S.C.C. 1.
10. Re-examining the basis of previous decisions, Smith v. Allwright, 321 U.S. 649 (1944).
11. Sakshi v. Union of India, A.I.R. 2004 S.C. 3566.
12. Payne v. Tennessee, 501 U.S. 808, 827 (1991).
13. B.Shama Rao v. Union Territory of Pondicherry, A.I.R. 1967 S.C. 1480.
14. Krishna Kumar v. Union of India, A.I.R. 1990 S.C. 1782.
15. Prithi Pal Singh Bedi v. Union of India, A.I.R. 1982 S.C. 1413.
16. Arunkumar Agarwal v. State of Madhya Pradesh, A.I.R. 2011 S.C. 3056.
17. Mohd. Saud v. Shaik Mohfooz, A.I.R. 2009 Ori 46.
18. Central Board of Dawoodi Bohra Community v. State of Maharashtra, A.I.R, 2005 S.C. 752.
19. Harsh Dhingra v. State of Haryana, (2001) 9 S.C.C. 550.
20. Suganthi Suresh Kumar v. Jagadesan, A.I.R. 2002 S.C. 681.
21. In re, The Special Courts Bill, A.I.R. 1979 S.C. 478.
22. Manipur Adm. V. Bira Singh, A.I.R. 1965 S.C. 87.